Method of protecting plants from pathogens with cyanomethyl aryl sulfonates

ABSTRACT

Fungus or bacteria pathogenic to plants are inhibited by applying to the locus to be protected therefrom a biocidally effective amount of a cyanomethyl arylsulfonate represented by the formula RSO3CH2CN where R

United States Smith et al.

a} a l t [1 1 3,903,298 [4 1 Sept. 2, 1975 METHOD OF PROTECTING PLANTSFROM PATI-IOGENS WITH CYANOMETHYL ARYL SULFONATES [75] Inventors:Herbert Q. Smith, Malvern; Sameeh Said Toukan, Phoenixville, both of(Under Rule 47) [21] Appl. No.: 385,495

I [52] US. Cl 424/303; 424/275 [51] Int. Cl AOln 9/14 [58] Field ofSearch 424/303; 260/456 R, 456 P [56] References Cited UNITED STATESPATENTS 10/1949 Harris et al. .l 424/303 l2/l972 Colin ct al. 260/456 ROTHER PUBLICATIONS Cox et al., Chem. Abst., Vol. 72, (1970), 78,673c.Lichtenberger et al., Chem. Abst., Vol. 43, (1949), p. 2941-2942.

Primary ExaminerJerome D. Goldberg Assistant ExaminerAllen J. Robinson[57] ABSTRACT Fungus or bacteria pathogenic to plants are inhibited byapplying to the locus to be protected therefrom a biocidally effectiveamount of a cyanomethyl arylsulfonate represented by the formula RSO CHCN where R is X or Xn n 4 I m 13 Claims, No Drawings METHOD OFPROTEC'EHNG PLANTS FRUM PATHOGENS Wl'llH CYANUMETHYL ARYL SULFONATESThis invention concerns a method of protecting plants from pathogens andplant diseases by treatment of the locus to be protected with acyanomethyl arylsulfonate.

Many of the organisms that inhabit the soil subsist on living plants andmay injure the roots and other underground portions, others may attackthe crown of the plant, while still others are capable of damaging thestem and other above-ground portions of the plant. Fungi, bacteria andlike plant pathogens attack a broad spectrum of plants including fieldcrops, truck crops, cereals and grasses, and ornamental and houseplants, including corn, soybeans, cotton, beets, sugar beets, oats,peanuts, onions, alfalfa, apples, peaches, beans, lettuce, celery,potatoes and others. The seriousness of the problem is enhanced whenplants are grown year after year in the same soil because the ready foodsupply nourishes the pathogens.

Cyanomethyl benzenesulfonate and cyanomethyl toluenesulfonate are knowncompounds: see Preparation and Reactions of a-CyanoalkylBenzenesulfonates, H. W. Turner, Univ. Microfilrns, Pub. No. 3082(1952)(Chern. Abs. 47, 2726a); .l. Lichtenberger and C. Faure, Bull Soc.Chim. France 1948, pp. 995-1001 (Chem. Abs. 43, 2941i). Neitherreference suggests that eyanomethyl benzenesulfonates might haveactivity against plant pathogens.

, In accordance with this invention a cyanomethyl arylsulfonate isapplied to the locus to be protected (i.e., the soil, a seedling, plant,or plant part) in sufficient amount to kill or otherwise effectivelyinhibit the development of soil and other fungi and bacteria patho genieto plants. The cyanornethyl arylsulfonate useful in the process of thisinvention is represented by the formula RSO CH CN where R is selectedfrom the group consisting of m-fi where X is independently hydrogen,halogen (i.e., chlorine, bromine, iodine or fluorine), alkyl or alkoxy(e.g., having from 1 to 18 carbon atoms, preferably 1 to 4, i.e., loweralkyl and lower alkoxy), NO ,CN, CF CONl-l SO NH l-l NCOO, OOH, YSO orOOCY, where Y is lower alkyl, n is an integer of 1 to 5 and m is aninteger of 1 to 3. The preferred compounds are those of the aboveformulae wherein X is hydrogen, halogen, lower alkyl or nitro.

The cyanomethyl arylsulfonates embodied herein are generally effectiveas fungicides and bactericides while being minimally phytotoxie to theplants sought to be protected using biocidally effective dosages. Ingeneral, application in the range of from about 0.1 pound to aboutpounds of the active agent per acre of surface treated gives effectivecontrol of the pathogen. Although a smaller range of about 0.1 to about5lb./acre is obviously preferred, the optimum amount will depend uponenvironmental factors, including the specific compound used, soil type,method of application climatic conditions, crop response, stage of plantdeveland.

oprnent at time of treatment, etc. The, optimum dosage in a specifictreatment can be readily determined by one having ordinary skill in theart. The compounds are generally effective against most of the moreprominent genera of plant pathogens, including species of Rhizoctonia,Pythium, Fusariurn, Verticillium, Sclerotinia, Aphanomyces, Asocochyta,Phytophthora, Thielaviopsis, Monilinia, Alternaria, Glomerella,Xanthomonas, Abrugo candida, Aspergillus, Botrytis, Cerospora,Cladosporium, Erysiphe, Fusicladium, Helminthosporium, Penicillum,Plasmopara, Septoria and Taphrina.

The cyanomethyl arylsulfonates are liquids or crystalline solids whichare insoluble in water, but are very soluble in a variety of typicalsolvents, for example, acetone, diaeetone alcohol, dimethylformamide,xylene, isopropanol, ethanol, methanol, benzene, methyl chloroform andothers. The agent may be formulated for application in the field asdispersions or solutions in organic solvents or emulsifiable oils. Toprepare the dispersion a suitable wetting agent may be added which aidsin the preparation of the formulation and which also serves to helppenetration of the compound into soil and plant surfaces. Suitabledispersion concentrates may be prepared with or without suspendingagents by ball milling or other fine grinding techniques. Suspendingagents will be selected from the various agents readily available, suchas lignin sulfonates, bentonite, dilute solutions ofMethocel cellulosederivative, and the like. Formulations may also be prepared as emulsionconcentrates for dilution with water for field applications. These maybe prepared by the use of suitable solvents such as xylene, heavyaromatic naphtha, isophorone, benzene, heptane, heavy mineral oils,kerosene, and other solvents immiscible with water, with the addition ofa suitable anionic, cationic, or nonionic emulsifying agent such aslong-chain alkyl benzenesulfonates or polyglyeol ethers. In lieu of saiddis persion or oilin-water emulsion, the compounds may be prepared andapplied merely as a solution in an organic solvent, such as thosesolvents mentioned above, or in such water-miscible solvents asdiaeetone alcohol, acetone, dimethyl sulfoxide, dimethylformamide,phosphoric acid esters, etc. The latter solutions can also be dilutedwith water to the desired concentrations. The compounds are preferablyapplied as formulations of wettable powders which are prepared by directgrinding of the compound with a blend of suitable carrying agent such asattapulgite, bentonite, kieselguhr and the like. It is desirable togrind such a blend in a hammer mill so that 99% will pass through a 325mesh screen. wettable powders may also be prepared by absorbing asolution of the compound in a solvent such as xylene or acetone on apowdered clay as attapulgite or diatomaeeous earth. All wettable powderpreparations may contain a dispersing agent such as a lignin sulfonateand a wetting agent such as an alkylaryl polyether glycol. Theconcentration of the active agent will, in general, range from about0.01 to about by weight of the total formulation, i.e., of the combinedweight of the active agent and the carrier medium, whether liquid or-/and powder. The techniques of preparing pesticidal formulations bycompounding carriers with the active agent are well known to thoseacquainted with the art.

While a preferred method of utilizing the agents is to apply theformulation to the soil to prevent infection of seedlings by thepathogenic organisms, other methods used to achieve essentially the sameresults, wherein, for example, the formulation is contacted with theseed in the hopper box of the planting apparatus prior to the plantingoperation. These methods also eliminate any organisms borne on the seeditself.

The cyanomethyl arylsulfonates are conveniently prepared by reactingsubstantially equimolar amounts of glycolonitrile and the appropriatearylsulfonyl chloride precursor, at a temperature ranging from about to100C., preferably 0 to 25C. The products are liquids at room temperatureor solids which melt at rather moderate temperatures. Illustrativeprocedures for preparing representative species of the cyanomethylarylsulfonates embodied herein are next presented All structures ofsynthesized compounds were confirmed by elemental analyses and infraredspectra.

EXAMPLE 1 Cyanomethyl benzenesulfonate, A pale, straw-colored oilyliquid,n,, "l.523l

EXAMPLE 2 Cyanomethyl p-toluenesulfonate,

Method of preparation: 8.1 g (0.1 mole of glycoloni- EXAMPLE 6Cyanomethyl p-bromobenzenesulfonate, obtained in 44% conversion from thereaction of pbromobenzenesulfonylchloride with glycolonitrile accordingto the procedure of Example 4. The product is a white solid, m.p. 5759C.

EXAMPLE 7 The iodo analog, cyanomethyl p-iodobenzenesulfon' ate, a whitesolid, m.p. 8790C., is similarly prepared (in 73% conversion) byreacting glycolonitrile with piodobenzenesulfonyl chloride.

EXAMPLE 8 Cyanomethyl p-chlorobenzenesulfonate, obtained in 51%conversion from the' reaction of ptrile (70% aqueous solution) is added.to a cooled (l520C.) mixture of 9.5 g (0.05 mole) of ptoluenesulfonylchloride in 20 ml. of 1,2- dimethoxy ethane and 50 ml. distilled water.A solution of 2.1 g (0.05 mole) of NaOH in 50 ml. distilled water isadded slowly with stirring at 2025C. over a period I of 6.5 hours,maintaining the pH of the reaction mixture at about 8. The insolublematerial is filtered off, washed with cold water, and dried at 40C.under vacuum to yield 6.8 g (64% conversion) of the product, a lightbrown solid, m.p. 48-5O.5C.

EXAMPLE 3 Cyanomethyl 2-thiophenesulfonate,

EXAMPLE 4 Cyanomethyl m-nitrobenzenesulfonate,

Preparation: The technique of Example 2 is used to react glycolonitrilewith m-nitrobenzenesulfonyl chloride The product is recovered from thereaction mixture by filtration and recrystallized from ethanol. Thedried product (45% conversion) is an amber solid, m.p. 66-69C.

EXAMPLE 5 Cyanomethyl p-fluorobenzenesulfonate, obtained in 87%conversion from the reaction of pfluorobenzenesulfonyl chloride withglycolonitrile according to the procedure of Example 3. The product is alight pinkish liquid,n l.5O82.

chlorobenzenesulfonyl chloride with glycolonitrile according to theprocedure of Example 3. The product is a colorless liquid,n,, l.5442.

EXAMPLE 9 Cyanomethyl 3,4-dichlorobenzenesulfonate, obtaiped in 88%conversion from the reaction of 3,4-

dichlorobenzenesulfonyl chloride with .glycolonitrile according to theprocedure of Example 3. The product -is recovered as a slightly pinkish,viscous liquid which,

on standing at room temperature, crystallizes out as! a light pinksolid, m.p. 4649C. I

.' EXAMPLE l0 Cyanomethyl 2,4,5-trichlorobenzenesulfonate, obtained in65% conversion from the reaction of 2,4,5-trichlorobenzenesulfonylchloride with glycolonitrile according to the procedure of Example,4.The product is a white solid, m.p. -8 3C.

EXAMPLE l l -Cyanomethyl 2,4-dinitroberizenesulfonate, obtained in 77%conversion from the reaction of 2,4-dinitroben-F zenesulfonyl chloridewith glycolonitrile. The product is a light yellow solid, m.p. 7275C.

EXAMPLE l2 tests known as the Spore Germination test and the BactericidePrimary test. The Spore Germination test is a laboratory -test conductedin concavities in a glass slide in which seven day old potato dextroseagar cultures of the spores 'Monilinia fructicola, Alternariabrassicola, and Glomerella cingulata are treated with 1,000, 100, 10,and l.ppm of the test agent. The formulated chemical (10% concentrationin xylene) is serially diluted with distilled water to obtainconcentrations of 2,000, 200, 20, and 2 ppm. One drop of the 2 ppmconcentration is placed in each of the first three concavities in theslide and then one drop of the 20 ppm concentration is placed in each ofthe next three concavities and the same is done for the 200 and 2,000

ppm concentrations;

The slides are kept at room temperature for 24 hours to allow thechemical solution in the concavities to dry. Spores are now washed fromthe surface of the agar cultures with distilled water containing :l%dextrose. Each spore suspension is filtered through four layers ofcheesecloth and diluted with additional dextrose water to obtain 50,000spores per ml. Two drops of a spore suspension of one of the organismsis added to each of the four concavities containing the four drieddilutions of the test chemical. The same is done with the two re mainingorganisms and the eight remaining concavities on the slide. Ten ml. ofdistilled water is added to the filter paper in each plate and a glasssupport rod laid on top of the paper. An agglutination slide is placedon the rod and the dish cover put in place.

The plates are incubated at 18 to 20C. for 24 hours, and the slides areobserved under the microscope and germination or no germination recordedfor each chemical concentration.

The rating of an agent run through the spore germination screen isassigned as follows:

The Bactericide Test is conducted with treated assay dishes and seededagar plates, wherein the formulated chemical (10% concentration inxylene) is serially diluted with distilled water in two tubes to obtainconcentrations of 2,000 and 200 ppm. Usually the first twoconcentrations obtained in the spore germination test are used as thetwo tests and conducted at the same time. Assay disks are dip treatedand the disks are allowed to dry for 24 hours.

A bacterial suspension (Xant/wmonas pruni) is made by washing a 24 hourold nutrient agar slant culture with ml. of sterile, distilled water. 2ml. of this suspension is added to 125 ml. of warm, melted nutrient agarin a flask. The seeded agar is then poured into 100 X mm. Petri plates.After the seeded agar has solidi fied and cooled, the treated disks areplaced on the surface. Four disks, representing two rates of two testchemicals, are placed in each dish. After 24 hours the plates areobserved and the diameter of the zone of in hibition, including disk, isrecorded. The rating of an agent run through the bacterial assay diskscreen is as signed as follows:

The results of the screening tests on the above representativecyanomethyl arylsulfonates are as follows:

Example Spore Germination Bactericide No. Rating Rating l l 3 0 l2 3 0*3 on Altemaria l on Monilia and Glomerella In another test, the soilfungicide effectiveness of representative compounds is determined bytreating seeds of sugar beet, cucumber and cotton with a dry claycarrier formulation of the material, and mixing the formulation withsoil infested with Pythium sp. at rates of 5, 15, and 50 lb./acre. oftotal active ingredient (including that retained by the seeds.) Thepercentage control of the soil organism is determined from the number ofemerged healthy seedlings compared to that of the untreated checksample. Control of the fungus at 5 lb./acre indicates excellent soilfungicidal properties. Referring to representative compounds screened,those labeled above as Examples 3 and 5 show excellent results ininhibiting such organism growth, Examples 2 and 9 give good results, andExamples 1 and 4 give fair '20 pounds per acre of a cyanomethylarylsulfonate represented by the formula RSO CH CN where R is wherein Xis independently hydrogen, halogen, lower alkyl or nitro, and n is aninteger of l to 5.

2. The method of claim 1 wherein the biocidally effective amount ofcyanomethyl arylsulfonate is within the range of about 0.1 to about 5lb. per acre.

3. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl benzenesulfonate.

4. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-toluenesulfonate.

5. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl 3,4-dichlorobenzensulfonate.

6. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-fluorobenzenesulfonate.

7. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl m-nitrobenzenesulfonate.

arylsulfonate is cyanomethyl 2,4-dinitro'benzenesulfonate.

-12. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl pentachlorobenzenesulfonate.

- .13.-The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl 2,4,5-trichlorobenzene-

1. A METHOD OF INHIBITING FUNGI OR BACTERIA PATHOGENIC TO PLANTS WHICHCOMPRISES APPLYING TO SAID FUNGI, BACTERIA OR THE LOCUS THEREOF ABIOCIDALLY EFFECTIVE AMOUNT WITHIN THE RANGE OF ABOUT 0.1 POUND TO ABOUT20 POUNDS PER ACRE OF A CYANOMETHYL ACRYSULFONATE REPRESENTED BY THEFOMMULA RSO3CH2CN WHERE R IS
 2. The method of claim 1 wherein thebiocidally effective amount of cyanomethyl arylsulfonate is within therange of about 0.1 to about 5 lb. per acre.
 3. The method of claim 1wherein the cyanomethyl arylsulfonate is cyanomethyl benzenesulfonate.4. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-toluenesulfonate.
 5. The method of claim 1 wherein thecyanomethyl arylsulfonate is cyanomethyl 3,4-dichlorobenzensulfonate. 6.The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-fluorobenzenesulfonate.
 7. The method of claim 1 whereinthe cyanomethyl arylsulfonate is cyanomethyl m-nitrobenzenesulfonate. 8.The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-bromobenzenesulfonate.
 9. The method of claim 1 whereinthe cyanomethyl arylsulfonate is cyanomethyl p-iodobenzenesulfonate. 10.The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl p-chlorobenzenesulfonate.
 11. The method of claim 1 whereinthe cyanomethyl arylsulfonate is cyanomethyl2,4-dinitrobenzenesulfonate.
 12. The method of claim 1 wherein thecyanomethyl arylsulfonate is cyanomethyl pentachlorobenzenesulfonate.13. The method of claim 1 wherein the cyanomethyl arylsulfonate iscyanomethyl 2,4,5-trichlorobenzenesulfonate.